document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1039933>Question 1039933</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Restricting the domain to make a one-to-one function.\r<BR>\n" );
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document.write( "can someone help me for this please? i really don't know. help me :( </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #654686 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=654686\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This requires that a function pass both the vertical and horizontal line test.<BR>\n" );
document.write( "y=x^2 is a function.  But it is not 1:1, for y=4 has two possible x values, -2 and 2.<BR>\n" );
document.write( "y=x^2 for x>=0 is 1:1.  It passes the horizontal line test. It is a function, but the domain has been restricted so that x may only be positive.\r<BR>\n" );
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